Small airway disease

Small airways disease comprise of a group infectious as well as non-infectious conditions that affect the small airways (i.e. airways that are more peripheral to the main bronchi and proximal bronchioles (4 the 14 generation) - arbitrarily considered to be those with an internal diameter of ≤2 mm ).

Pathology

While some authors consider this term synonymous with a bronchiolitis , conditions such as asthma may also fall under this group . There are also many other conditions that can affect or be associated with small airways which include:

• hypersensitivity pneumonitis 
• sarcoidosis - pulmonary manifestations of sarcoidosis
• respiratory bronchiolitis interstitial lung disease
• micro carcinoid tumourlets - diffuse idiopathic pulmonary neuroendocrine hyperplasia  
• follicular bronchiolitis
• drug-induced small airways disease
• connective tissues diseases
  • rheumatoid arthritis
  • pulmonary manifestations of inflammatory bowel disease
  • Sjogren syndrome

Radiographic features

CT

There are many CT features associated with small airways disease, which include:

• direct signs
  • thickened peripheral airways: may only be seen in the proximal portion
• indirect signs (many of these features may be nonspecific on their own):
  • air trapping 
  • subsegmental atelectasis 
  • mosaic lung attenuation
  • centrilobular nodules  
  • tree-in-bud changes

Siehe auch:

• mosaikartige Verdichtungen der Lunge
• Hypersensitivitätspneumonitis
• pulmonale und mediastinale Sarcoidose
• air trapping
• tree in bud-Muster
• Bronchiolitis
• zentrilobuläre Lungennoduli
• respiratory bronchiolitis interstitial lung disease
• follikuläre Bronchiolitis
• diffuse idiopathic pulmonary neuroendocrine hyperplasia

und weiter:

• Bronchitis
• peri-bronchial cuffing